Anode



Sept, .1 l, 1934.

A. HENDERSON 1,973,345 I moms Filed July :51, 1951 Patented Sept. 11, 1934 v PATENT OFFICE axons Alexander Henderson, Detroit, Mich, alsignor to The American Brass Company, Waterbury, Conn., a corporation of Connecticut.

Application July 31, 1931,- Serial No. 554,285

2 Claims.

This invention relates to an anode for electroplating, and has for an object to provide an anode which will give a higher eiliciency and better distribution of corrosion during the plating process.

- It is also an object to provide an anode in which there is a large'external surface in contact with the electrolyte in proportion to the amount of metal used in the anode.

Another-object of the invention is to provide an anode in which at no time during the life of the anode will the surface exposed to the electrolyte be reduced to any marked extent, and thus the surface exposed to the electrolyte will be substantially constant or at least be reduced only a relatively small extent during the entire life of the anode. In other words, the material is so located that as it corrodw or is eaten away .the surface exposed to the electrolyte is not materially or objectionably decreased.

A further object of the invention is to provide an anode in which the scrap orwaste is reduced to a minimum or practically nothing. and which for a given amount of active metal less metal is required to be suspended in the platingtank than is the case with ordinary anodes, and which also requires less metal to be carried in stock.

A further object is to provide an anode which" mension, and therefore for a given'surface exposure to the electrolyte the user of the anode will require only approximately one-half or less of weight of metal to equip a plating tank.

Other and further objects of the invention will appear from a more detailed description of the invention taken in connection with the accompanying drawing forming a part of this specifica tion.

In this drawing:

Fig. 1 is a side elevation of an anode constructed according to this invention;

.Fig. 2 is an end view thereof; and

Figs. 3 and 4 are end views on a somewhat smaller scale of similar anodes of a somewhat modified construction.

. In electroplating it is desirable that a large surface of the active metal be exposed to the electrolyte, and it is also desirable that the amount of this surface be maintained as uniform aspossible for satisfactory operation. Various attempts have been made to secure these results, but the anodes so produced have been compli- 55 cated and expensiveand furthermore they did not secure the results to the extent desired.

by making the anode in the form of a hollow tube, preferably oval in cross section as this gives a better distribution of the metal with more uniform corrosion during the plating operation, and also provides a better distribution or placing of the exposed surface for greater eiiiciency and uniformity in the plating operation.

Referring to the. accompanying drawing, in Figs. 1 and 2 the anode-10 is shown as a hollow tube of oval shape in cross section with the walls of substantially uniform thickness throughout.

It can be suspended in the electrolyte by any suitable means, that indicated involving providing the opposite side walls with transverse openings 11 to receive a rod to pass through the eye 12 of the suspending hook 13 to hook over the usual conductors or bus bars 14 and conduct the necessary current to the anode. The walls of this anode are continuous and the anode may be formed in various ways. It is preferred that the metal be worked to give a uniform and dense texture as this provides better operation in the plating process. Thus a round billet may be longitudinally pierced and rolled to form a tube as in the Mannesmann process, which not only forms a tube from the billetbut works the metal into a dense uniform texture. The tube thus formed can be given the desired oval shape by passing it through rolls having grooves of the desired shape, or by drawing the tube through suitably shaped dies. This provides a wrought anode in which the metal is dense and worked so that it is of uniform texture and is a better anode.

It ishowever not necessary that the wrought anode be worked by piercing and rolling as described, but the metal may be worked by rolling 10o i to form an oval tube 15 with the abutting edges coming, together at 16 in one of the edge portions of the tube. In Fig. 4 the strip is folded toform a tube 17 with theabutting edges coming together at 18 in one of the flatter sides of the tube. These seams may be leftasmerely abutting joints or they 1 10 Y may be welded or brazed as desired. In either case whether pierced as in Figs. 1 and 2 or folded as in Figs. 3 and 4, it will be evident that there is produced a wrought anode in which the active metal 5 has a smooth outer surface where it 'is in contact with the electrolyte, and the metal is all located where it can be used effectively. Although it is preferred that'the tubes be worked and of oval shape in cross section as shown, they need not necessarily be so, although this is the much pre ferred construction. The tubes can be cast in this shape and they can be given different shapes in cross section, but the wrought or worked tube is preferred as giving a metal of denser and more uniform texture, and the oval shape is preferred as it gives a more uniform corrosion of the metal throughout the exposed surface. In square, rectangular or similar shapes there is more corrosion at the sharp corners than at other portions of the surface, and therefore the eating away of the iii ",involves a. large amount of scrap or waste which roan of course. be cleaned and remelted and put into new anodes, but this involves handling of iconsiderablemetal, and metalwhich is useless in .the metal plating process. With my improved anode however, there is nocentral core of any kind to be discarded andit will be evident that all or practically all of the metal can be used without materially decreasing the surface exposed to the electrolyte, or at least without decreasing this exposed surface' to an objectionable extent. In other words all of the metal of this anode is located at or adjacent the outer or exposed surface of the anode, and for] a given amount of metal there is a smaller proportional decrease in the exposed surface in contact with the electrolyte as the metal corrodes, and therefore the entire anode can be used for the plating process without decreasing the exposed surface to such an extent as to be objectionable or greatly reduce the efllciency of the plating process. Thus for example if the oval opening through the tube represents substantially one-half the cross sectional area within the outer outline of the tube, then it will be evident that this improved anode will weigh only anodes.

about half as much as a solid anode of the same outside dimensions, and therefore if the outline of the opening represents the smallest exposed surface which could be used efficiently then the entire metal of this new anode can be used efflciently and there will be no scrap or waste of metal. Therefore at no time during the life of the anode will the surface exposed to the electrolyte be reduced to a marked or objectionable extent because for the same amount of active metal the exposed surface will remain substantially uniform, or at least will not be reduced to less than or percent of the original surface.

This is important in other ways, as it will be evident that for the user to equip a plating tank with the same amount of useful metal only about half the weight of metal is required to equip the tank of what would be required with the old solid This also means a considerable saving in the weight of metal carried in anodes in stock. This further effects a considerable saving in handling as there is less metal to be handled in the anodes themselves, and there is practically no scrap. It will of course be obvious that the anodes can be made of various sizes and the ratio of the outside dimensions or surface with respect to the inside dimensions or surface may be determined depending on'the amount of reduction of the surface exposed to the electrolyte which is permissible in the plating operation without an objectionable decrease in efllciency and uniformity of plating. It will of course be understood that these anodes can be made of any metal or composition desired for the plating operation involved, such for example as copper, nickel, chromium, brass, silver etc.

Having thus set forth the nature of my invention, what I claim is:

1. A soluble anode for electroplating comprising a hollow tube of active metal of oval shape in cross section, the opening through the tube being also of oval shape, and both of said ovals being of similar shape and direction.

2. A soluble anode for electroplating comprising a hollowtube of active metal of oval shape in cross section, the opening through the tube being also of oval shape, both of said ovals being of similar shape and direction and the inner oval being of a size that the tube contains not more than approximately one half the metal which would be contained in a solid bar of the same cross section as the tube.

ALEXANDER HENDERSON. 

